1. Technical Field
The present invention relates to an apparatus for driving a gyroscope sensor and a method thereof.
2. Description of the Related Art
Generally, a gyroscope sensor is a sensor measuring angular velocity using Coriolis force Fc of a vibrating object.
In this case, the Coriolis force at the gyroscope sensor is represented by the following Equation 1.Fc=2 mVΩ  [Equation 1]
Where Fc: Coriolis force, m: mass, V: velocity, Ω: angular velocity.
Referring to the above Equation 1, the gyroscope sensor is vibrated by a driving signal to generate velocity V, thereby measuring the Coriolis force Fc. In this case, when the velocity V defined by the driving and the sensed Coriolis force Fc are known, the angular velocity Ω of the gyroscope sensor may be calculated since the mass m is known.
That is, the angular velocity Ω is represented by ‘Fc/2 mV’ and therefore, the angular velocity Ω may be obtained by measuring the Coriolis force Fc while driving the object m at a predetermined velocity V.
In particular, the Coriolis force Fc, the velocity V, and the angular velocity Ω are a vertical vector to each other. For example, in order to obtain Z-directional angular velocity Ωz, velocity Vx may be given in an X direction and Coriolis force Fc_y in a Y direction may be measured. In addition, in order to measure the angular velocities Ωx and Ωy in X and Y directions, the velocity Vz is given in a Z direction and Coriolis forces Fc_y and Fc_x in the X and Y directions may be measured.
That is, in order to measure the angular velocity in several directions, the vibration direction of the vibrating object needs to be changed and a sampling rate needs to be increased so as to increase a measurement frequency bandwidth of the angular velocity.
For example, in order to obtain the measurement frequency bandwidth of 0 to 100 Hz, the sampling needs to be performed 200 times for at least 1 sec.
Generally, the gyroscope sensor vibrates the object having a high Q factor as described in Japanese Patent Laid-Open No. 2010-197062 or Korean Patent 10-0657424 and is thus driven in the Z axis to measure angular velocities in the X and Y axes and then, is driven in the X-axis direction by switching a moving direction of the object so as to measure the angular velocity in the Z axis. To this end, a driving stop time for switching a direction is needed.
However, the apparatus for driving a gyroscope sensor according to the prior art does not include a special technical device for stopping during the driving and therefore, consumes much time from the driving to the stopping, thereby increasing a settling time. Therefore, the apparatus for driving a gyroscope sensor according to the prior art is inappropriate to apply for a multi-axis gyroscope sensor.